Introduction to Astronomy

Indeed, as soon as the offspring falls upon the earth, they look at the head of the infant; if they see a mass of hair, as if in curls, they foreknow that a male will next be born. In this way, with twin curls, they expect twins. For among those women, it is also a sign of prosperous fortune for the master whenever the birth emerges with the fetal sacoriginal: "folliculo" intact. Then, measuring the number of future generations, they examine the sac of the first-born infant while it is still attached to the mother's womb before it is released; in this, however many knots or pebble-like lumps they find, they count as many future births. If none are found, they foreknow that she will bear nothing further, doubting nothing in these matters unless perhaps the sequence was confused by a prior miscarriage. Thus, in this manner, while the use of experiments holds such authority among common minds, so too among physicians is the foresight of their own care firm through the certainty of experiments.

This foresight belongs to those for whom experience in that art is firmer regarding natural things and those surrounding nature: through the seasons of the year, the climates of the lands, and a certain genus of humorsThe four bodily fluids (blood, phlegm, yellow bile, black bile) believed to control health. in human bodies. Furthermore, they measure to what extent one part prevails over the rest, then what is healthy or harmful for whom, and even the increases, decreases, state, and alterations of the body's discomfort. They observe the passive nature of those things which are contrary to nature, mediating between both types by comparison within fixed limits.

This, however, is done through the very alterations of the elements' motions, and the causes of these alterations and motions: the powers of the stars. Not being unskilled in these motions, they recall the power of the Sun original symbol: ☉ as heat, the power of the Moon original symbol: ☽ as moisture, and the motions of both stars and constellations along with their mixing. Therefore, the more worthy this kind of skill is than common ones, the closer it is to our own.

The duty of medicine is more worthy in one part: first, to subtly perceive the materials of bodies, namely the natures of the elements; then, to mix them in bodies while maintaining proportionality; and finally, to treat the motions of accidents arising from the approach and retreat of the mixture by natural necessity.

The duty of astrology, however, in its secondary part, is to measure the motions of the elements and the alterations of the seasons from the motion of the stars, as well as the motions of accidents both of the world itself and its parts—here generally, there specifically. Therefore, just as the physician is first instructed by sensible experiments and then advanced to the properties of nature, considering this species hot, that one cold, dry, or moist, and appropriate for this or that disease; so the astrologer, from a certain sensible instruction of experiments, is advanced to the natural properties of the celestial bodies. He holds the Sun to be hot, the Moon moist, and thus holds certain the power and nature of each of the stars and constellations by the reason of their effects.

Thus, common skills are indeed particular. Medicine and astrology would seem more universal, because each embraces the integrity of its own kind; except that we estimate astrology to be as much higher as its subject matter is more worthy. Indeed, medicine is exercised in the natures of the elements and in the alterations of bodies arising from their composition, state, and accidents; astrology, however, is entirely consumed in the motion and natures of celestial bodies and their effects throughout the inferior world. The physician gives his labor to the alterations of the elements. The astrologer follows the motions of the stars as the causes of elementary alteration. Thus, the science of the constellations and stars is to all skills as much as celestial things are to earthly...